Technical Field
The present invention relates to the use of outdoor air for cooling data centers and, more particularly, to maintaining contamination level in the facility by using air contamination data and to predicting the effective lifetime of air conditioner filters in data centers.
Description of the Related Art
With the increasing computational power of IT equipment, the energy consumed for cooling can grow to be similar to the energy consumed for computation. One way to reduce cooling is the use of outdoor air for cooling when temperature, relative humidity, and air contamination are within acceptable ranges. One concern for using outside air for cooling is the introduction of gaseous and particulate contamination in the data centers. In general air filters can be used for removing the contamination for the air but they can impede air flow across the filter, requiring larger blower to maintain air flow, and can increase the overall maintenance cost of the data centers.
Air filters can effectively remove particular and gaseous contamination, but they are expensive to maintain. Contamination may be highly location-dependent, with different contaminants present in different quantities depending on the geographic area. As a result, filter replacement time can vary substantially according to data center settings and the orientation of its air intake. A recommended filter replacement time is usually provided by manufacturers based on an average value between best- and worst-case scenarios and may not actually reflect the realities of a given installation.
The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) issues guidelines regarding gaseous and particular contamination in data centers. In 2011, the ASHRAE indicated that data centers should maintain an environment having a copper reactivity rate of less than 300 angstroms per month and a silver reactivity rate of less than 200 angstroms per month to maintain reliable equipment operation. Corrosion can be caused by both gaseous and particular contamination, and particulate contamination may have further negative mechanical and electrical effects.
Cooling systems that perform heat transfer with external air provide economical heat dissipation but involve a greater exposure to external contaminants. Leaks are inevitable and impose a slow air exchange between the clean air inside the data center and the contaminated external air.